On the Hadronic Beam Model for Gamma-Ray Production in Blazars
On the Hadronic Beam Model for Gamma-Ray Production in Blazars
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DOI：
10.1086/306555
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发表时间：
1998-01
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影响因子：
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通讯作者：
J. Beall;W. B. N. R. Laboratory;Csiceosr;G. University;S. College;Usa;D. Physics;U. Lodz;Poland
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文献类型：
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作者：
J. Beall;W. B. N. R. Laboratory;Csiceosr;G. University;S. College;Usa;D. Physics;U. Lodz;Poland
我们考虑了耀blazar中γ射线产生的一个模型，在该模型中，当射流通过活动星系核的宽窄线区域传播时，相对论性的、高度准直的电子-质子束与致密的云相互作用。在质子束通过云的传播过程中，等离子体波的激发过程成为一个重要的能量损失机制，特别是对于轻度相对论性质子束。考虑到电子-质子束的无碰撞损失，我们计算了电子束与云的强子碰撞中产生的中性介子衰变产生的γ射线的期望光谱。该模型可以解释Mrk 421的x射线和TeV γ射线（低发射态和高发射态）是由带电介子衰变产生的二次对同步辐射和中性介子衰变产生的γ射线发射引起的。然而，云不能太热太密。否则，TeV γ射线会被云中的轫致辐射衰减，二次对由于逆康普顿散射的主导作用而不能有效地产生同步耀斑。Mrk 421在EGRET能量范围内观测到的不变γ射线发射不能用中性介子衰变产生的γ射线来描述，前提是束流中的质子谱可以用简单的幂定律很好地描述。这些γ射线可能只是由次级对散射软不变x射线产生的，而软不变x射线可能起源于吸积盘的内部。
We consider a model for γ-ray production in blazars in which a relativistic, highly collimated electron-proton beam interacts with a dense, compact cloud as the jet propagates through the broad- and perhaps narrow-line regions of active galactic nuclei. During the propagation of the beam through the cloud, the process of excitation of plasma waves becomes an important energy-loss mechanism, especially for mildly relativistic proton beams. We compute the expected spectra of γ-rays from the decay of neutral pions produced in hadronic collisions of the beam with the cloud, taking into account collisionless losses of the electron-proton beam. This model may explain the X-ray and TeV γ-ray (both low and high emission states) of Mrk 421 as a result of synchrotron emission of secondary pairs from the decay of charged pions and γ-ray emission from the decay of neutral pions for the plausible cloud parameters. However, clouds cannot be too hot and too dense. Otherwise, the TeV γ-rays can be attenuated by the bremsstrahlung radiation in the cloud and the secondary pairs are not able to efficiently produce synchrotron flares because of the dominant role of inverse Compton scattering. The nonvariable γ-ray emission observed from Mrk 421 in the EGRET energy range cannot be described by the γ-rays from decay of neutral pions provided that the spectrum of protons in the beam is well described by a simple power law. These γ-rays might only be produced by secondary pairs scattering the soft nonvariable X-rays, which might originate in the inner part of the accretion disk.